> ## Documentation Index > Fetch the complete documentation index at: https://docs.thesys.dev/llms.txt > Use this file to discover all available pages before exploring further. # Models & Compatibility ## Models & Pricing C1 is family of API endpoints that use different underlying LLM models. The pricing is based on the model family and the amount of tokens used. Pricing is based on model name irrespective of the kind of endpoint you use. For example, using the [embed](/api-reference/endpoints/embed) endpoint with `c1/anthropic/claude-sonnet-4/v-*` is priced the same as using the [visualize](/api-reference/endpoints/visualize) endpoint with the same model. Generally speaking, a model name is more than just the model of the LLM it uses. It also includes the version of the model, the set of components available for use in the UI, and any other metadata. This guide is called "Models" and not "API Versions" because typically you'd pass the API version to the `model` parameter in the request to the LLM compatible endpoints of C1. ## Model Versions & SDK Requirements Thesys supports all major models — including every model from OpenAI, Anthropic, and Google, as well as the full catalog of models available via OpenRouter. All models use the same model string format: `c1/provider/model/v-*` * `c1` prefix: marks the request as a C1 Generative UI request * `provider/model`: standard provider/model path (follows the OpenRouter naming convention) * `v-*`: the Thesys API version — see [API Changelog](/api-reference/model-changelog) for details on each release Only `v-20251230` is currently supported for OpenRouter models. ### Model Coverage **OpenAI, Anthropic & Google** are accessed through first-party APIs, giving you full compliance coverage, zero data retention guarantees, and rigorous quality assurance. These are the primary recommended providers and the ones we actively test and optimise against. See the [Recommended Models](#recommended-models) section for a curated list. For example, to use Claude Opus 4.6: `c1/anthropic/claude-opus-4.6/v-20251230`. **All other models** are available via OpenRouter — any model in the OpenRouter catalog works with the same `c1/provider/model/v-*` format. You can configure provider constraints such as ZDR and data residency via the `provider` parameter in your API request — see [OpenRouter Provider Routing](https://openrouter.ai/docs/guides/routing/provider-selection). For example, to use Qwen 3.5: `c1/qwen/qwen3.5-397b-a17b/v-20251230`. Compliance and availability are not guaranteed for OpenRouter-routed models. OpenRouter may route requests across multiple underlying providers, each with their own data retention and availability policies, which are outside of Thesys's control. You can use the `provider` parameter to restrict routing to specific providers or enforce constraints such as ZDR — see [OpenRouter Provider Routing](https://openrouter.ai/docs/guides/routing/provider-selection) for configuration options. For compliance-sensitive workloads, use OpenAI, Anthropic, or Google models via the Thesys API. ### Recommended Models #### Embed Endpoint Models **Model:** `c1/anthropic/claude-sonnet-4.6/v-20260331` **Install Dependencies:** ```bash theme={null} npm install @thesysai/genui-sdk@~0.9.0 @crayonai/react-ui@~0.9.16 @crayonai/react-core@~0.7.7 ``` **Model:** `c1/openai/gpt-5.2/v-20260331` **Install Dependencies:** ```bash theme={null} npm install @thesysai/genui-sdk@~0.9.0 @crayonai/react-ui@~0.9.16 @crayonai/react-core@~0.7.7 ``` **Model:** `c1/anthropic/claude-sonnet-4/v-20251230` **Install Dependencies:** ```bash theme={null} npm install @thesysai/genui-sdk@~0.7.15 @crayonai/react-ui@~0.9.9 @crayonai/react-core@~0.7.6 ``` **Model:** `c1/openai/gpt-5.2/v-20251230` **Install Dependencies:** ```bash theme={null} npm install @thesysai/genui-sdk@~0.7.15 @crayonai/react-ui@~0.9.9 @crayonai/react-core@~0.7.6 ``` **Model:** `c1/openai/gpt-5/v-20251230` **Install Dependencies:** ```bash theme={null} npm install @thesysai/genui-sdk@~0.7.15 @crayonai/react-ui@~0.9.9 @crayonai/react-core@~0.7.6 ``` **Model:** `c1/google/gemini-3-pro/v-20251230` **Install Dependencies:** ```bash theme={null} npm install @thesysai/genui-sdk@~0.7.15 @crayonai/react-ui@~0.9.9 @crayonai/react-core@~0.7.6 ``` Reasoning for Gemini 3 Pro cannot be disabled, which increases the Time-to-First-Bite (TTFB). This might lead to high user-perceived latency. **Model:** `c1/google/gemini-3-flash/v-20251230` **Install Dependencies:** ```bash theme={null} npm install @thesysai/genui-sdk@~0.7.15 @crayonai/react-ui@~0.9.9 @crayonai/react-core@~0.7.6 ``` #### Visualize Endpoint Model **Model:** `c1/anthropic/claude-sonnet-4/v-20251230` **Install Dependencies:** ```bash theme={null} npm install @thesysai/genui-sdk@~0.7.15 @crayonai/react-ui@~0.9.9 @crayonai/react-core@~0.7.6 ``` #### Artifact Endpoint Model **Model:** `c1/artifact/v-20260130` **Install Dependencies:** ```bash theme={null} npm install @thesysai/genui-sdk@~0.8.3 @crayonai/react-ui@~0.9.16 @crayonai/react-core@~0.7.6 ``` #### Free Models Requests and responses for free models will be stored and might be used to improve services and offerings. **Model:** `c1/google/gemini-3.1-pro-free/v-20260331` **Model:** `c1/google/gemini-3.1-flash-lite-free/v-20260331` ### Other Model Versions | C1 Model (Latest Version) | genui-sdk | react-ui | react-core | | :------------------------------------------ | :-------- | :------- | :--------- | | `c1/anthropic/claude-3.5-sonnet/v-20250709` | \~0.6.27 | \~0.8.14 | \~0.7.6 | | `c1/anthropic/claude-3.7-sonnet/v-20250709` | \~0.6.27 | \~0.8.14 | \~0.7.6 | | `c1-latest` | -- | -- | -- | | `c1-202504XX*` | -- | -- | -- | ## Model Specifications These specifications apply to all versions of each model family. | C1 Model | LLM | Input Price / M tokens | Cached Input (Read) | Cached Input (Write) | Output Price / M tokens | Context Window | Max Output | | :----------------------------------- | :--------- | :--------------------- | :------------------ | :------------------- | :---------------------- | :------------- | :--------- | | `c1/anthropic/claude-sonnet-4` | Sonnet 4 | \$3.00 | \$0.30 | \$3.75 | \$15.00 | 200K | 64K | | `c1/openai/gpt-5.2` | GPT 5.2 | \$1.75 | \$0.175 | -- | \$14.00 | 400K | 128K | | `c1/openai/gpt-5` | GPT 5 | \$1.25 | \$0.125 | -- | \$10.50 | 400K | 128K | | `c1-exp/anthropic/claude-sonnet-4.5` | Sonnet 4.5 | \$3.00 | \$0.30 | \$3.75 | \$15.00 | 200K | 64K | | `c1-exp/anthropic/claude-haiku-4.5` | Haiku 4.5 | \$1.00 | \$0.10 | \$1.25 | \$5.00 | 200K | 64K | | `c1-exp/anthropic/claude-3.5-haiku` | 3.5 Haiku | \$0.80 | \$0.80 | \$1.00 | \$4.00 | 200K | 8192 | | `c1-exp/openai/gpt-4.1` | GPT 4.1 | \$2.00 | \$0.50 | -- | \$8.00 | 1M | 32K |